Tacit Knowledge, also known as implicit knowledge or implied knowledge is knowledge that is hard to express, define or translate, and therefore more difficult to transfer by way of verbalizing it or writing it down. This might include personal knowledge, experience, intuition, insight, and even intuition. I think the definition should be "the capacity to know a piece of information implicitly" and then move forward from there. It is my belief that there are three distinct forms of Tacit Knowledge, each related to one another (and dependent upon the knowledge base itself), but all requiring the ability to think abstractly, in advance, about both the known and the unknown, which is inherent in the human brain, as is the case with reasoning.
Now, some people think that there is no difference between the three types of knowledge, but they are wrong. There is a clear distinction between explicit knowledge which is something you have been taught from birth, that we all believe is true (and even need for some purposes), and implicit knowledge, which is something that comes naturally to us, is that which we come to realize unconsciously, such as when we use a word or phrase in a conversation, and then we automatically incorporate in our thinking about the meaning of what we just said, even if we don't really understand the underlying meaning or how it applies to our immediate circumstances. Now, I would submit to you that most people do learn some implicit or tacit knowledge in their lives at some point, through some personal experience. This implicit or personal knowledge is not abstract or hidden, it is something that we all possess, but are too afraid to bring to the surface, because of its uncomfortable implications.
Michael Polanyi's work as a professor of philosophy at the University of Reading, England, offers up many lessons on the importance of tacit knowledge and the necessity for universities to facilitate this important process. In his book, The Power of Words, he writes that we can all become better citizens and human beings by learning to appreciate the ways in which words are used, both by those who know us and by those who do not. In this way, we can all become more aware citizens, better people, because through the implicit understanding that we all possess regarding the uses and purposes of language, we all can be better judges of other human beings and things. As he says: "verbal culture runs through all our institutions and politics". In other words, as humans interacting in a society, the power of words is greater than ever, and this inherent reality can be changed.